The present invention relates to a method for separating fibers from a section of wood;
When producing mechanical pulp from wood, the fibres are separated from the wood by means of the wood being pressed against a grindstone or metal disc. Water is added to the process, on the one hand to carry off the excess heat and an the other hand to conduct the wood fibres away.
At a defined flow of water, the temperature can be held in the range of 100-200.degree. C. preferably around 150.degree. C. This facilitates the process of extraction of the fibres from the unit of wood since on the one hand the latter is moistened and on the other hand it is heated. However, the heating must not attain such a level as to cause an undesired molecular breakdown of the cellulose. On the other hand, the morphological complex of cellulose, hemicellulose and lignin is to be loosened.
By means of this method, the fibre is not damaged as much as it is in cold grinding, with a great deal of water, where essentially all the excess heat is carried off. In cold grinding, the fibre is broken off or torn off at too many locations, and the paper produced from cold-ground pulp thus loses strength. A moderate shredding of the fibre is aimed for, however, in order to increase the opacity of the paper, compared to chemical pulp.